Tensioner Cylinder Connections with Multiaxial Degrees of Freedom

Abstract

A coupler having two degrees of axial freedom couples a hydro-pneumatic cylinder to a tensioner ring of a riser tensioner mounted to a platform. A post extends along an axis of the cylinder and an intermediate sleeve is disposed around the post to form a post annulus. An outer sleeve is secured to the tensioner ring and defines a cavity into which the post and intermediate sleeve are inserted so that an annulus is formed between the sleeve and the outer sleeve. The Outer sleeve is coupled to the intermediate sleeve so that the outer sleeve may pivot on the coupling between the outer sleeve and the intermediate sleeve relative to the intermediate sleeve. The intermediate sleeve is coupled to the post so that the intermediate sleeve may pivot on the coupling between the intermediate sleeve and the post relative to the post.

Description

[0001]The application claims the benefit of and priority to U.S. Provisional Patent Application No. 61 / 557,231, filed Nov. 8, 2011, entitled “Tensioner Cylinder Connections with Multiaxial Degrees of Freedom” to Aksel, et al., which application is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates in general to marine riser tensioners and, in particular, to a push up tensioner that accommodates riser tilt with tensioner cylinder connections with multiaxial degrees of freedom.[0004]2. Brief Description of Related Art[0005]Offshore production platforms must support production risers from oil or gas wells that extend to the platform from subsea wells. For platforms that are fixed to the ocean floor this is readily accomplished and is well known in the art. However, for subsea completions in deep water that require the use of floating platforms, such as tension leg platforms (TLPs) or semi-submer...

AI Technical Summary

Benefits of technology

The invention is a push up riser tensioner that can handle heavy loads on a tension leg platform. It uses a coupler with multiple degrees of freedom to connect the cylinder with the tensioner ring, allowing for efficient use of space and reduced corrosion. The design also avoids high pressure accumulation and eliminates the need for additional deck structure to support the riser tensioner.

Problems solved by technology

However, for subsea completions in deep water that require the use of floating platforms, such as tension leg platforms (TLPs) or semi-submersible platforms, supporting risers present significant problems.

While use of both TLPs and RAM type push up tensioners is desired, because of the varying riser tilt, RAM style push-up tensioners constructed to date are not currently suitable for use with TLPs.

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